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addition of paraffin i.e., it should give a clear solution with
water. It is, however, preferable to use rectified spirits 60-70
over-proof which can be bought free of duty by teaching institu-
tions on application to the Inland Revenue Board.

Methylated spirit contains, in addition to ethyl and methyl
alcohols, water, fusel-oil, acetalde-
hyde, and acetone. It may be
freed from aldehyde by boiling
with 2—3 per cent, solid caustic
potash on the water-bath with an
upright condenser for one hour, or
if larger quantities are employed,
a tin bottle is preferable, which
is heated directly over a small
flame (see Fig. 38). It is then
distilled with the apparatus shown
in Fig. 39. The bottle is here
surmounted with a T-piece hold-
ing a thermometer. The distil-
lation is stopped when most of the
spirit has distilled and the ther-
mometer indicates 80°. A further
purification may be effected by
adding a little powdered perman-
ganate of potash and by a second
distillation, but this is rarely ne-
cessary. The same method of
purification may be applied to
over-proof spirit, which will hence-
forth be called spirit as distinguished from the purified product
or absolute alcohol.

Ethyl Alcohol, C2H5.OH


Commercial absolute alcohol may be used for the preparations
which follow. It is obtained by distilling crude spirits of wine
over quicklime, and usually contains about 0-5 per cent of

Properties.—Pure ethyl alcohol boils at 78-3°, and has a
sp. gr. of 0793 at I5°- It mixes with water in all'proportions

COHEN'S ADV. p.o.c.                                              E

FIG. 38.